The CAS Registry Mumber 112372-91-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,2,3,7 and 2 respectively; the second part has 2 digits, 9 and 1 respectively. Calculate Digit Verification of CAS Registry Number 112372-91: (8*1)+(7*1)+(6*2)+(5*3)+(4*7)+(3*2)+(2*9)+(1*1)=95 95 % 10 = 5 So 112372-91-5 is a valid CAS Registry Number.